Context:

Equivalent: The terms mean the same thing and can always be used interchangeably.
Very similar: The terms mean almost the same thing, and in most cases they can be used interchangeably.
Somewhat similar: The meanings of the terms overlap, but in some cases they cannot be used interchangeably.
Not very similar: The terms mean almost completely different things, and in most cases they cannot be used interchangeably.
Unrelated: The terms mean completely different things, and they can never be used interchangeably.

Task:

Read the following terms: {concept_1}, {concept_2}.

How similar are the terms?

Instructions:

1. Think through the problem step-by-step, but provide only the final answer as a JSON object.
2. The expected JSON format is: {{"similarity": similarity}}.